1. Field of the Invention
2. Description of the Prior Art
An internal gear pump of the above type is also referred to as an annular gear pump. The annular gear and the pinion represent the pump elements and are also referred to as the outer rotor and the inner rotor. DE 38 27 573 A1 has disclosed an internal gear pump whose annular gear is driven by an electric motor. The delivery chambers disposed between the teeth of the two pump elements of the internal gear pump are covered in the axial direction by a thrust washer. A helical spring embodied as a compression spring, which is prestressed against the thrust plate, assures that axial play is equal to zero during the starting of the internal combustion engine. Between the electric motor and the annular gear, an Oldham coupling is provided, which can compensate for an axial offset between the pump and the electric motor.